Poly[[aqua(μ-4,4′-bipyridyl-κ2N:N′)bis(μ-formato-κ2O:O′)iron(II)] tetrahydrate]

In the title compound, {[Fe(CHO2)2(C10H8N2)(H2O)]·4H2O}n, the FeII ion is coordinated by two 4,4′-bipyridyl (4,4′-bpy) ligands, three formate ligands and one water molecule. The slightly distorted octahedral FeN2O4 coordination results from the N atoms of two bridging 4,4′-bpy ligands, the O atoms of two bridging HCOO− anions of anti–anti mode, all in trans positions around the metal centre, and the O atoms of one terminal HCOO− anion and of one water molecule. The bridging formate ligands link the metal ions into chains that are further connected via 4,4′-bpy ligands into a framework structure. The three-dimensional structure is stabilized by extensive O—H...O hydrogen bonding. The crystals were twinned containing a 0.84:0.16 racemate